Continuous ambulatory peritoneal dialysis, also abbreviated "CAPD", can frequently be used directly by the patient, without medical supervision. Various types of apparatus and systems are known and have been proposed to assist in or completely replace the natural purification functions.
Existing CAPD apparatus have drawbacks, principally due to danger of infection, usually caused by the inevitable contact of the hands of the user with fittings and coupling members which the patient, necessarily, has to handle in a non-sterile environment, even if gloves, adhesive ribbons, and sterilized gauzes are used. Another source of possible infection is due to the possible contamination of dialysis liquid by draining liquid from a preceding dialysis operation. It is practically impossible to eliminate traces of contaminated fluid which are retained in the tubes or fittings of apparatus, and will then be entrained in freshly supplied dialysis liquid for re-introduction into the abdominal cavity, and thus lessening the efficacy on a subsequent dialysis irrigation.